191 research outputs found
RADIO FREQUENCY--MICROWAVE DOUBLE RESONANCE AS A TOOL IN THE ANALYSIS OF MICROWAVE SPECTRA
No full textThis work was supported by the National Science Foundation. S. H. Autler and C. H. Townes, Phys. Rev. 100, 703 (1955).""Author Institution: Department of Chemistry, Harvard University,The practical application of radio frequency-microwave double (RFMDR) as a spectroscopic technique in the analysis of microwave spectra has been investigated. A high-power amplitude-modulated radio-frequency field applied to the Stark septum of a conventional waveguide provides a means of detecting microwave transitions, analogous to the situation in microwave-microwave double resonance (MMDR). The sensitivity of the technique compares favorably with that of MMDR and Stark modulation. Nearly prolate asymmetric top molecules with allowed a-type transitions are especially amenable to the technique due to the presence of favorable radio-frequency transitions between asymmetry doublets. Accidental near degeneracies of dipole-connected rotational levels are also useful. A description of a RFMDR spectrometer using conventional as well as slightly modified Stark cell waveguides will be presented. Limitations and special problems posed by the nature of radio-frequency circuits will be discussed, and examples of applications together with suggestions for other possible uses will be given
Exclusive electroproduction of rho0 and J / psi mesons at HERA
No full textExclusive production of rho(0) and J/psi mesons in e(+)p collisions has been studied with the ZEUS detector in the kinematic range 0.25 < Q(2) < 50 GeV2, 20 < W < 167 GeV for the rho(0) data and 2 < Q(2) < 40 GeV2, 50 < IS' < 150 GeV for the J/psi data. Cross sections for exclusive rho(0) and J/psi, production have been measured as a function of Q2, W and t. The spin-density matrix elements r(00)(04), r(1-1)(1) and Rer(10)(5) have been determined for exclusive rho(0) production as well as r(00)(04) and r(1-1)(04) for exclusive J/psi production. The results are discussed in the context of theoretical models invoking soft and hard phenomena
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